Mechanical parameters of thermally modified ash wood determined by compression in radial direction
Keywords:
Fraxinus excelsior, mechanical properties, Thermowood, wood density, wood modification.Abstract
Mechanical parameters of ash wood (Fraxinus excelsior) subjected to compression in radial direction, before and after its thermal modification and measured at moisture content close to the equilibrium moisture content of wood exposed in and outside (4 and 12%) were compared. Thermal modification of wood was performed at 190°C or 200°C for 2 h in industrial conditions. During the measurements, the moisture content of the modified and control samples was identical. The parameters compared included: modulus of elasticity, stress at proportionality limit, relative linear strain at proportionality limit and accumulated elastic energy. Changes in the mechanical parameters of wood induced by its thermal modification were found to depend on the modification temperature and wood moisture content.Downloads
References
Andersson, S. 2006. A study of the nanostructure of the cell wall of the tracheids of conifer xylem by x-ray scattering. University of Helsinki report series in physics HU-PD135: 1-35.
Arnold, M. 2010. Effect of moisture on the bending properties of thermally modified beech and spruce. Journal of Materials Science 45(3):669-680.
Bekhta, P.; Niemz, P. 2003. Effect of high temperature on the change in color, dimensional stability and mechanical properties of spruce wood. Holzforschung 57(5):539-546.
Boonstra, M. J.; Van Acker, J.; Tjeerdsma, B. F.; Kegel, E. F. 2007. Strength properties of thermally modified softwoods and its relation to polymeric structural wood constituents. Annals of Forest Science 64(7):679-690.
Borrega, M.; Kärenlampi, P.P. 2008. Mechanical behavior of heat-treated spruce (Picea abies) wood at constant moisture content and ambient humidity. European Journal of Wood and Wood Products 66(1):63-69.
Bourgois, J.; Janin, G.; Guyonnet, R. 1991. Measuring colour: a method of studying and optimizing the chemical transformations of thermally-treated wood. Holzforschung 45(5):377-382.
Brischke, C.; Welzbacher, C.R.; Brandt, K.; Rapp, A.O. 2007. Quality control of thermally modified timber: Interrelationship between heat treatment intensities and CIE L*a*b* color data on homogenized wood samples. Holzforschung 61(1):19-22.
Chow, S. Z.; Mukai, H.N. 1972. Effect of thermal degradation of cellulose on wood-polymer bonding. Wood Science 4(4):202-208.
Clauss, S.; Pescatore, C.; Niemz, P. 2014. Anisotropic elastic properties of common ash (Fraxinus excelsior L.). Holzforschung 68(8):941-949.
Fengel, D.; Wegener, G. 1984. Wood, chemistry, ultrastructure, reactions. Walter de Gruyter & Co., Berlin.
Gibson, L. J.; Ashby, M.F. 1997. Cellular solids. Structural and properties. Second edition. Cambridge Univ. Press.
González-Peña, M.M.; Hale, M.D.C. 2009. Colour in thermally modified wood of beech, Norway spruce and Scots pine. Part 2: Property predictions from colour changes. Holzforschung 63(4):394-401.
Green, D.W.; Winandy, J.E.; Kretschmann, D.E. 1999. Mechanical properties of wood - wood as an engineering material. General Technical Report FPL-TR 113, U.S. Department of Agriculture, Forest Service, Forest Products Laboratory, Madison, WI.
Gündüz, G.; Korkut, S.; Korkut, D.S. 2008. The effects of heat treatment on physical and technological properties and surface roughness of Camiyanı Black Pine (Pinus nigra Arn. subsp. pallasiana var. pallasiana) wood. Bioresource Technology 9(7):2275-2280.
Gündüz, G.; Korkut, S.; Aydemir, D.; Bekar, I. 2009. The density, compression strength and surface hardness of heat-treated Hornbeam (Carpinus betulus L.) wood. Maderas. Ciencia y tecnologia 11(1):61-70.
Johansson, D.; Morén, T. 2006. The potential of colour measurement for strength prediction of thermally treated wood. European Journal of Wood and Wood Products 64(2):104-110.
Koji, M.; Yasuhiro, W.; Takato, N. 2013. Effect of thermal treatment on fracture properties and adsorption properties of Spruce wood. Materials 6(9):4186-4197.
Kollmann, F. F. P.; Côté, W.A. J. 1984. Principles of wood science and technology I. Solid wood. Springer-Verlag, Berlin.
Korkut, S.; Aytin, A. 2015. Evaluation of physical and mechanical properties of wild cherry wood heat-treated using the thermowood process. Maderas. Ciencia y tecnologia 17(1):171-178.
Korkut, S.; Hiziroglu, S. 2009. Effect of heat treatment on mechanical properties of hazelnut wood (Corylus colurna L.). Materials & Design 30(5):1853-1858.
Li-Shi, J.; Kocaefe, D.; Zhang, J. 2007. Mechanical behavior of Québec wood species heattreated using ThermoWood process. Holz als Roh- und Werkstoff 65(4):255-259.
Mazela, B.; Zakrzewski, R.; Grześkowiak, W.; Cofta, G.; Bartkowiak, M. 2004. Resistance of thermally modified wood to basidiomycetes. Electronic Journal of Polish Agricultural Universities 7(1): wood series.
Militz H.; Altgen, M. 2014. Processes and properties of thermally modified wood manufactured in Europe. ACS Symposium Series 1158:269-285.
Mohareb, A.; Sirmah, P.; Pétrissans, M.; Gérardin, F. 2012. Effect of heat treatment intensity on wood chemical composition and decay durability of Pinus patula. European Journal of Wood and Wood Products 70:519-524.
Moliński, W.; Fabisiak, E.; Szwaba, T. 2010. Properties of thermally modified Ash wood (Fraxinus americana) in the aspect of its affinity to water. Ann WULS-SGGW For Wood Technol 72:27-31.
Murata, K.; Watanabe, Y.; Nakano, T. 2013. Effect of thermal treatment on fracture properties and adsorption properties of Spruce wood. Materials 6(9):4186-4197.
Niemz, P.; Clauss, S.; Michel, F.; Hansch, D.; Hansel, A. 2014. Physical and mechanical properties of common ash (Fraxinus excelsior L.). Wood Research 59(4):671-682.
Olek, W.; Bonarski, J.T. 2008. Texture changes in thermally modified wood. Archives of Metallurgy and Materials 53(1):207-211.
Peters, J.; Pfriem, A.; Horbens, M.; Fischer, S.; Wagenführ, A. 2009. Emissions from thermally modified beech wood, their reduction by solvent extraction and fungicidal effect of the organic solvent extracts. Wood Materials Science and Engineering 4(1-2):61-66.
PN-77/D-04229 Drewno. Oznaczanie wytrzymałości na ściskanie w poprzek włókien (Wood. Determination of compression strength across the grain - standard in Polish). Thermowood® Handbook. 2003. Finnish Thermowood Association, Helsinki (http://www.vanhoorebeke.com/docs/Thermowood%20handboek.pdf).
Viitaniemi, P.; Jämsä, S.; Viitanen, H. 1997. Method for improving biodegradation resistance and dimensional stability of cellulosic products. United States Patent Nº 5678324 (US005678324).
Weiland, J.; Guyonnet, R. 2003. Study of chemical modifications and fungi degradation of thermally modified wood using DRIFT spectroscopy. Holz als Roh- und Werkstoff 61(3):216-220.
Winandy, J.E.; Rowell, R.M. 1984. The chemistry of wood strength. In: The Chemistry of Solid Wood. ACS Symposium Series 208.Ed. Rowell, R.M. American Chemical Society, Washington, DC. pp. 211-255.
Windeisen, E.; Bächle, H.; Zimmer, B.; Wegener, G. 2009. Relations between chemical changes and mechanical properties of thermally treated wood. Holzforschung 63(6):773-778.
